Selective photoinduced charge separation in perylenediimide-pillar[5]arene rotaxanes

Nicholas Pearce, Katherine E.A. Reynolds, Surajit Kayal, Xue Z. Sun, E. Stephen Davies, Ferdinando Malagreca, Christian J. Schürmann, Sho Ito, Akihito Yamano, Stephen P. Argent, Michael W. George, Neil R. Champness*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

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The ability to control photoinduced charge transfer within molecules represents a major challenge requiring precise control of the relative positioning and orientation of donor and acceptor groups. Here we show that such photoinduced charge transfer processes within homo- and hetero-rotaxanes can be controlled through organisation of the components of the mechanically interlocked molecules, introducing alternative pathways for electron donation. Specifically, studies of two rotaxanes are described: a homo[3]rotaxane, built from a perylenediimide diimidazolium rod that threads two pillar[5]arene macrocycles, and a hetero[4]rotaxane in which an additional bis(1,5-naphtho)-38-crown-10 (BN38C10) macrocycle encircles the central perylenediimide. The two rotaxanes are characterised by a combination of techniques including electron diffraction crystallography in the case of the hetero[4]rotaxane. Cyclic voltammetry, spectroelectrochemistry, and EPR spectroscopy are employed to establish the behaviour of the redox states of both rotaxanes and these data are used to inform photophysical studies using time-resolved infra-red (TRIR) and transient absorption (TA) spectroscopies. The latter studies illustrate the formation of a symmetry-breaking charge-separated state in the case of the homo[3]rotaxane in which charge transfer between the pillar[5]arene and perylenediimide is observed involving only one of the two macrocyclic components. In the case of the hetero[4]rotaxane charge separation is observed involving only the BN38C10 macrocycle and the perylenediimide leaving the pillar[5]arene components unperturbed.

Original languageEnglish
Article number415
Number of pages10
JournalNature Communications
Issue number1
Publication statusPublished - 20 Jan 2022

Bibliographical note

Funding Information:
NRC gratefully acknowledges the support of the UK Engineering and Physical Sciences Research Council (EP/S002995/1). We acknowledge Diamond Light Source for time on Beamline I19 under Proposal CY21755.

Publisher Copyright:
© 2022, The Author(s).

ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Physics and Astronomy(all)


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